CBI is also unable to solve this murder mystry.Who has killed Aarushi and why killed no one knows.

This is not a mystery, everyone knows what is the actual scene , it is just that CBI is not able to find solid proofs and evidence and on the basis of doubt, there is no concrete solution as of yet. It should be a good lesson for working family when they leave their wards in care of house maid without proper precautions.